Chain track for vehicles



Sept. 2, 1930. J. H. ROBERTSON 1,774,815

CHAIN TRACK FOR VEHICLES Filed March 8, 1929 2 Sheets-Sheet l Sept. 2, 1930. J. u. ROBERTSON CHAIN TRACK FOR VEHICLES 2 Shooter-Shoot 2 Filed larch 8. 1929 ATTOR/VfXJ Patented Sept. 2, 1930 UNITED s rres JOHN HOGG RIBEBTBON, OF LONDON', ENGLAND cam Timex non. .vnnrcms Application filed March 8, 1929, Serial No. 345,371, and in Great Britain April 5, 1928.

This invention relates to chain tracks for vehicles, either of the kind in which endless self-laying tracks are employed with the lower run of the track in driving contact wlth U the ground or of the kind in which endless chains are fittedover substantially co-planar 7 road wheels to constitute non-skid devices for use under difiicult surface conditions.

The shoe members of these chain tracks are commonly provided with metal or other ground plates rigidly secured to the shoe members themselves, which are connected together by pivotal bearings. In the case of overall non-skid chains, metal links are usual- 1 1y pivoted at each end of the shoe member and the other ends of said links are pivoted to the adjacent shoe members, while in the case of endless tracks or chain tracks, the rail sections or webs of adjacent links are ivoted together by transverse pins and ushes. These pivoted bearings are, however, extremely subject to wear at the pivot pins or bushes, so that the pins and bushes have to be replaced quite frequently.

It is the object of the present invention to provide a connection between metal shoe members which is simple in construction, gives great flexibility, is long wearing and does not require such frequent renewal.

According to the present invention, the metal or other rigid shoe members are connected in series by means of flexible connectors which are not pivoted to the shoe members but by reason of their inherent flexibility allow the chain formed of rigid shoe members so connected together, to follow the curve of the wheel.

These pivotless, flexible connectors are preferably made of multiple-ply rubberized fabric or like material, as used for pneumatic tires, and they are formed with enlarged I a heads at both ends whereby they can be engaged between successive shoe members, to which the said heads are secured by clamping plates, gripping jaws or similar engaging devices.

The invention is hereafter described with reference to the accompanying drawings, in

5 which Figure 1 is a part-sectional elevation of a track shoe for a self-laying track.

Figure 2 is a part-sectional side elevation of a short length of the track.

Figure 3 is a lan of the track shoe with one complete fa ric connector in position.

Figure 4 is a perspective view of a fabric connector.

Figure 5 is a plan view'of a track shoe designed to employ pairs of fabric connectors.

Figure 6 is a sectional view corresponding to the right half of Figure 1, showing adjustable means for clamping the connector in position.

Figure Fi ure 6.

eferring to Figures 1 to 4, the track shoe 7 is a sectional view on line 7-7 of comprises a ground plate ('1 having a curved lip'or rim b and two parallel ribs 0 pressed in the plate to form seatings for the main shoe member (2, these ribs extending transversely of the run of the track. The plate a is secured to the main shoe member d by bolts 6, the heads of which are recessed into the hollow backs of the ribs 0.

The opposite ends of the member (1 are provided with part cylindrical hollow bosses f with which the teeth of the driving or idler sprockets g engage as shown in dotted lines in Figures 1 and 2. As seen in Figures 1 to 3, the center of the member (Z consists of a hollow pyramidal box It with an arched or domed top, the interior of this box being divided by a central web 71, extending transversely of the run of the track, so as to provide two chambers with openings j at the front and rear of the member (1 respectively.

A jaw plate is is fitted between the track member 03 and the ground plate a, being held in place by bolts 6 which also assist to secure the ground plate to the main track member. The plate is is provided with upturned jaws k which correspond with the lower parts of the openings 1'.

Flexible connectors Z, see Figure 4, made of multiple-ply cord fabric with an exterior layer of rubber, similar to the outer covers of pneumatic tyres, are arranged between adjacent track shoes, the heads Z of these connectors belng engaged in the spaces or chambers on either side of the web 2', the parts being bolted together after the connectors have been fitted in place.

As seen in Figure 2, the heads of the fabric connectors Z are approximately of hexagonal shape, while the connecting bar or stem replaces the two adjacent apices of the hexabe seen that each connector, including the two heads and the connecting stem, is roughly of dumb-bell shape in side elevation; in plan view the connector may be of uniform width, as seen in Fi ure 8.

In the mod ification illustrated in Figure 5, the member at comprises two hollow b :xes h h arranged symmetrically on either side of the center line of the track, the chambers in the interior of these boxes receiving the respective headsl of two pairs of fabric connectors Z which are clamped in lace by jaw plates in'the manner already escribed.

The flexible connectors Z shown in Figures 1 to 5 may be reinforced by metallic plates or cores 1 extending along their central stems and provided, if desired, with hooked or headed ends Z enclosed inside the cord fabric interior Z.

The clamping or nipping devices formed by the jaws k and the openings j may be themselves adjustable; this may be done by providing for the jaw-plate k to be adjustable in position on the main shoe member (1, for example by the use of shims m fitted between the jaw plate 70 and the under surface of the main shoe member d at the position of the bolts e as illustrated in Figures 6 and 7 When the clamping devices require tightening, the bolts e are slackened and the bolts e removed so that one or more of shims m can be withdrawn from above the jaw plate is and re-insertedibelow the latter, between its under surface and the ribbed portion of the ground plate a.

It will be noted that the use of'these flexible connectors dispenses with the pivots between the track shoes, and therefore with the necessity for lubricating such pivots. The shoe members and the pivotless connectors are easily replaced and they may be adjusted as to pitch by raising or lowering the jawplates is in relationto the main shoe members d by the adjustment already mentioned.

It will be noted that the present invention provides a greater degree of. lasting flexibility than the customary pivotally connected track shoes, Where the initial flexibility of the pivots is rapidly reduced by mud, rust and other influences, which entail frequent dismantling and cleaning of the chain arts.

p Moreover, the improved chain track with fabric connectors presents a certain lon itudinal elasticity which cushionsthe shoe due to starting and to travelling over soft ground or rough surfaces, so that the life of the track is increased, and it retains its flexibility in the plane of the sprockets, without developing looseness in the lateral direction.

What I claim is 1. A chain track for vehicles, comprising rigid shoe members with intermediate. flexible connectors, said intermediate connectors being constructed of rubber-covered fabric having a central reinforcement, said connectors being formed with extremital heads engaged in the respective shoe members, and said reinforcement consisting of a metal plate having enlarged ends contained within the extremital heads of said connectors.

.2. A vehicle chain-track connecting member, consisting of a flexible rubber-covered fabrio'structure of approximately dumb-bell form, the extremital heads of said fabric structure being of an elongated hexagonal shape and their connectingl stem replacing two adjacent apices of the exagons.

3. A vehicle chain-track connecting member, consisting'of a flexible rubber-covered fabric structure with extremital heads, and a central reinforcement within said fabric structure, said reinforcement consisting of a metal plate with enlarged ends, said ends being contained within said extremital heads.

4. In a chain track for vehicles, the combination of a ground plate, a space block rigidly secured to said ground plate and adapted to engage the teeth of a driving sprocket, a flexible'member connectin said space block to the corresponding space %lock of an adjacent track shoe plate, said flexible member having enlarged heads at its extremities, said space block adapted to receive the enlarged head at one end of said flexible member, and a clamping device secured to said space block so as to engage said head for positive engage ment of said flexible connector to said space block.

5. In a chain track for vehicles, the combi nation of a ground plate, a space block ri idly secured to the back of said ground p ate and adapted to "engage the teeth of a driving sprocket, said space block being formed as a hollow box divided by an interior web to provide two compartments, a pair of flexible multiple-ply fabric connectors having enlarged heads at their extremities, one of said connector heads being engaged in each of said compartments, and a clamping device rigidly secured to said space block for clamping said connector heads in the respective compartments.

JOHN HOGG ROBERTSON. 

